Recently, technologies relating to eco-friendly vehicles using electrical energy as vehicle power have been actively developed in response to air pollution and the crisis of oil depletion. The eco-friendly vehicles include hybrid electric vehicles, fuel cell electric vehicles, electric vehicles, and the like.
Referring to FIG. 1, in a conventional inverter system for a vehicle for outputting a high output, for a high output, a motor is driven by connecting a plurality of switching elements S1 to S6 in parallel. However, in the conventional inverter system, the high output can be obtained by connecting the plurality of switching elements to the motor in parallel, but in a fuel economic driving mode in which a required output amount of a motor is relatively low, excessive switching and conduction losses occur in the switching elements such that there is limitation in that fuel efficiency of the vehicle is entirely lowered. Further, in the conventional inverter system for a vehicle, there is a limitation in that limp home driving is impossible when a failure such as disconnection or the like occurs between the motor and the inverter.